The present invention relates to disposable hygiene products and more specifically, to methods and apparatuses for processing disposable hygiene products. More specifically, the invention relates to cutting and applying segments of one web to attach to a disposable diaper.
The invention disclosed herein also relates to apparatus and methods for waste reduction. Generally, diapers comprise an absorbent insert or patch and a chassis, which, when the diaper is worn, supports the insert proximate a wearer's body. Additionally, diapers may include other various patches, such as tape tab patches, reusable fasteners and the like. The raw materials used in forming a representative insert are typically cellulose pulp, tissue paper, poly, nonwoven web, acquisition, and elastic, although application specific materials are sometimes utilized. Usually, most of the insert raw materials are provided in roll form, and unwound and applied in assembly line fashion. As in many manufacturing operations, waste minimization is a goal in web processing applications, as products having spliced raw materials cannot be sold to consumers. Indeed, due to the rate at which web processing machines run, even minimal waste can cause inefficiencies of scale.
In present systems, waste materials are recycled. However, the act of harvesting recyclable materials from defective product is intensive. That is, recyclable materials are harvested only after an identification of a reject product at or near the end of a process. The result is that recyclable materials are comingled, and harvesting requires the extra step of separating waste components. Therefore, it is beneficial to use up all of incoming rolls, so that a portion of the incoming rolls do not become waste. That objective is accomplished with the present invention
When manufacturing hygiene products, such as baby diapers, adult diapers, disposable undergarments, incontinence devices, sanitary napkins and the like, a common method of applying discrete pieces of one web to another is by use of a slip-and-cut applicator. A slip-and-cut applicator is typically comprised of a cylindrical rotating vacuum anvil, a rotating knife roll, and a transfer device. In typical applications, an incoming web is fed at a relatively low speed along the vacuum face of the rotating anvil, which is moving at a relatively higher surface speed and upon which the incoming web is allowed to “slip”. A knife-edge, mounted on the rotating knife roll, cuts a off a segment of the incoming web against the anvil face. This knife-edge is preferably moving at a surface velocity similar to that of the anvil's surface. Once cut, the web segment is held by vacuum drawn through holes on the anvil's face as it is carried at the anvil's speed downstream to the transfer point where the web segment is transferred to the traveling web.
Continual improvements and competitive pressures have incrementally increased the operational speeds of disposable diaper converters. As speeds increased, the mechanical integrity and operational capabilities of the applicators had to be improved accordingly.